@misc{MorelCastroFossatietal.2014,
  author    = {Morel, T. and Castro, Norberto and Fossati, Luca and Hubrig, Swetlana and Langer, N. and Przybilla, Norbert and Sch{\"o}ller, Markus and Carroll, Thorsten Anthony and Ilyin, Ilya and Irrgang, Andreas and Oskinova, Lida and Schneider, Fabian R. N. and Simon D{\´i}az, Sergio and Briquet, Maryline and Gonz{\´a}lez, Jean-Francois and Kharchenko, Nina and Nieva, M.-F. and Scholz, Ralf-Dieter and de Koter, Alexander and Hamann, Wolf-Rainer and Herrero, Artemio and Ma{\´i}z Apell{\´a}niz, Jesus and Sana, Hugues and Arlt, Rainer and Barb{\´a}, Rodolfo H. and Dufton, Polly and Kholtygin, Alexander and Mathys, Gautier and Piskunov, Anatoly E. and Reisenegger, Andreas and Spruit, H. and Yoon, S.-C.},
  title     = {The B fields in OB stars (BOB) survey},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {821},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41523},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-415238},
  pages     = {8},
  year      = {2014},
  abstract  = {The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects were observed over 20 nights with FORS2 and HARPSpol. Our preliminary results indicate that the fraction of magnetic OB stars with an organised, detectable field is low. This conclusion, now independently reached by two different surveys, has profound implications for any theoretical model attempting to explain the field formation in these objects. We discuss in this contribution some important issues addressed by our observations (e.g., the lower bound of the field strength) and the discovery of some remarkable objects.},
  language  = {en}
}
@article{HubrigFossatiCarrolletal.2014,
  author    = {Hubrig, Swetlana and Fossati, Luca and Carroll, Thorsten Anthony and Castro, Norberto and Gonzalez, J. F. and Ilyin, Ilya and Przybilla, Norbert and Schoeller, M. and Oskinova, Lida and Morel, T. and Langer, N. and Scholz, Ralf-Dieter and Kharchenko, N. V. and Nieva, M. -F.},
  title     = {B fields in OB stars (BOB): The discovery of a magnetic field in a multiple system in the Trifid nebula, one of the youngest star forming regions},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {564},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  organization    = {BOB Collaboration},
  issn      = {0004-6361},
  doi       = {10.1051/0004-6361/201423490},
  pages     = {5},
  year      = {2014},
  abstract  = {Aims. Recent magnetic field surveys in O- and B-type stars revealed that about 10\% of the core-hydrogen-burning massive stars host large-scale magnetic fields. The physical origin of these fields is highly debated. To identify and model the physical processes responsible for the generation of magnetic fields in massive stars, it is important to establish whether magnetic massive stars are found in very young star-forming regions or whether they are formed in close interacting binary systems. Methods. In the framework of our ESO Large Program, we carried out low-resolution spectropolarimetric observations with FORS 2 in 2013 April of the three most massive central stars in the Trifid nebula, HD 164492A, HD 164492C, and HD 164492D. These observations indicated a strong longitudinal magnetic field of about 500-600 G in the poorly studied component HD 164492C. To confirm this detection, we used HARPS in spectropolarimetric mode on two consecutive nights in 2013 June. Results. Our HARPS observations confirmed the longitudinal magnetic field in HD 164492C. Furthermore, the HARPS observations revealed that HD 164492C cannot be considered as a single star as it possesses one or two companions. The spectral appearance indicates that the primary is most likely of spectral type B1-B1.5 V. Since in both observing nights most spectral lines appear blended, it is currently unclear which components are magnetic. Long-term monitoring using high-resolution spectropolarimetry is necessary to separate the contribution of each component to the magnetic signal. Given the location of the system HD 164492C in one of the youngest star formation regions, this system can be considered as a Rosetta Stone for our understanding of the origin of magnetic fields in massive stars.},
  language  = {en}
}